The present invention relates to compositions for treating, for example, disinfecting, cleaning, soaking, conditioning and wetting contact lenses. More particularly, the invention relates to multi-purpose solutions useful in treating contact lenses, for example, for disinfecting contact lenses, for removing deposit material from contact lenses, for soaking, conditioning and/or wetting contact lenses and the like, which provide substantial comfort and acceptability benefits to the users of such solutions.
Contact lenses need to be periodically treated, for example, disinfected, cleaned, soaked and the like, on a regular basis because of the tendency for a variety of ocular and environmental contaminants, microbes and other materials to accumulate on the lenses and/or the need to provide the lenses in suitable condition for safe and comfortable wear. User compliance, that is users treating contact lenses on a regular and consistent basis, is important in order to promote ocular health and to avoid problems associated with contact lens wear. User compliance is enhanced when the treatment solution employed provides high degrees of lens wearer/user comfort and acceptability. Therefore, it would be advantageous to provide compositions for treating contact lenses which provide such comfort and/or are accepted by contact lens wearers/users of such compositions.
Fu U.S. Pat. No. 4,323,467 discloses an aqueous composition combining a poly(oxyethylene)-poly(oxypropylene) substituted ethylenediamine surfactant, a germicidal agent, a viscosity builder, a tonicity agent, a sequestering agent and water for treating rigid contact lenses. This patent discloses a germicide, such as thimerosal and/or benzalkonium chloride, in a concentration of 0.0005%-0.05%. The Fu patent does not disclose the use of any specific buffer. Although the compositions of the Fu patent have multiple utilities, there is a potential for eye discomfort and/or irritation, for example, because of the relatively high concentrations of germicide and the apparent lack of pH control.
British Patent 1,432,345 discloses a contact lens disinfecting composition including an ophthalmically acceptable biguanide in a total amount of from 0.0005% to 0.05% by weight. This British patent discloses that the solution preferably has a pH of from 5 to 8 and employs a phosphate buffer. The patent also discloses employing additional bactericides, thickening agents and non-ionic surfactants, as well as disodium EDTA in concentrations of at least 0.1%. Although these compositions are effective as contact lens disinfectants, they do pose a risk of eye discomfort and/or irritation, for example, because of the relatively high concentrations of biguanide and EDTA employed.
Ogunbiyi et al U.S. Pat. No. 4,758,595 discloses an aqueous solution of a biguanide in an amount of 0.000001 to 0.0003% weight percent in combination with a borate buffer system, EDTA, and one or more surfactants. This U.S. patent additionally states that conventional buffers, other than the borate buffer, can be used but only in conjunction with increased amounts of biguanide. Thus, the general conclusion of this U.S. Patent is that if reduced amounts of biguanide are to be used, a borate buffer is essential. Although such compositions are useful, the potential for ocular discomfort and irritation in a relatively large percentage of the total population still exists, for example, because of the requirement that a borate buffer be employed.
There continues to be a need to provide new contact lens treatment systems, for example, multi-purpose solutions, that effect the desired treatment or treatments of the lens and, at the same time, provide substantial, preferably enhanced, lens wearer/user comfort and acceptability.
New compositions for treating contact lenses have been discovered. The present compositions, that is multi-purpose aqueous solutions, include antimicrobial components, preferably reduced concentrations of antimicrobial components, in combination with phosphate buffers and viscosity inducing components to provide the desired antimicrobial activity and performance effectiveness and, importantly, substantial, preferably enhanced, lens wearer/user comfort and acceptability benefits. These compositions are surprising and unexpected in view of the above-noted prior art which employs relatively large concentrations of antimicrobial components and/or buffering systems other than phosphate buffering systems and/or does not employ viscosity inducing components. In addition, the inclusion of one or more other components in the present compositions is effective in providing additional beneficial properties to the compositions, and preferably provide further lens wearer/user comfort and acceptability benefits. The present compositions have a multitude of applications, for example, as disinfecting, cleaning, soaking, wetting and conditioning compositions, for contact lens care, while providing substantial lens wearer/user comfort and acceptability. The present compositions preferably increase user compliance, that is promote regular and consistent contact lens care, and, ultimately, lead to or facilitate better ocular health.
In one embodiment of the present invention, multi-purpose solutions for contact lens care are provided. Such solutions comprise an aqueous liquid medium; an antimicrobial component in an amount effective to disinfect a contact lens contacted with the solution; a surfactant in an amount effective in cleaning a contact lens contacted with the solution; a phosphate buffer component in an amount effective in maintaining the pH of the solution within a physiologically acceptable range; a viscosity inducing component present in an effective amount; and a tonicity component in an amount effective in providing the desired tonicity to the solution.
The antimicrobial component may be any suitable, preferably ophthalmically acceptable, material effective to disinfect a contact lens contacted with the present solutions. Preferably, the antimicrobial component is selected from biguanides, biguanides polymers, salts thereof and mixtures thereof, and is present in an amount in the range of about 0.1 ppm to about 3 ppm or less than 5 ppm (w/v). The preferred relatively reduced concentration of the antimicrobial component has been found to be very effective, in the present compositions, in disinfecting contact lenses contacted with the compositions, while at the same time promoting lens wearer/user comfort and acceptability.
Any suitable, preferably ophthalmically acceptable, surfactant component which is effective in cleaning contact lenses may be employed. The surfactant component preferably is non-ionic and, more preferably, is selected from poly(oxyethylene)-poly(oxypropylene) block copolymers and mixtures thereof.
Any suitable, preferably ophthalmically acceptable, viscosity inducing or thickening agent may be included in the present compositions. The viscosity inducing component preferably is selected from cellulosic derivatives and mixtures thereof and is present in an amount in the range of about 0.05% to about 0.5% (w/v). Without wishing to limit the invention to any particular theory of operation, it is believed that the presence of a viscosity inducing component at least assists in providing the lens wearer/user comfort and acceptability benefits of the present invention, which promote regular and consistent contact lens care and ultimately lead to or facilitate better ocular health. The present combinations of components, for example, including such viscosity inducing components, are effective in providing the degree of lens wearer/user comfort and acceptability benefits described herein.
Although any suitable, preferably ophthalmically acceptable, tonicity component may be employed, a very useful tonicity component is a combination of sodium chloride and potassium chloride.
The present compositions preferably include an effective amount of a chelating component. Any suitable, preferably ophthalmically acceptable, chelating component may be included in the present compositions, although ethylenediaminetetraacetic acid (EDTA), salts thereof and mixtures thereof are particularly effective. More preferably, the present compositions include chelating components in effective amounts less than about 0.05% (w/v) and still more preferably 0.02% (w/v) or less. Such reduced amounts of chelating component in the present compositions remain effective in providing the desired chelating and/or sequestering functions while, at the same time, are better tolerated in the eye, thereby reducing the risk of user discomfort and/or ocular irritation.
Various combinations of two or more of the above-noted components may be used in providing at least one of the benefits described herein. Therefore, each and every such combination is included within the scope of the present invention.
These and other aspects of the present invention are apparent in the following detailed description, examples and claims.